1. Field of the Invention
The present invention relates to an optical pickup to be used in a disk apparatus (e.g. DVD recorder or DVD player) and, particularly, in which the soldered connection of an end portion of a cable extending from an element with a main substrate cannot be broken.
2. Description of the Related Art
An optical pickup will be described schematically with reference to FIG. 7. A plastic slide base 2 is engaged in a back-and-forth movable manner with a pair of left and right guide rails 1 that extend in the radial direction X of a disk D. A printed-wiring main substrate 3 is mounted on one surface of the slide base 2, while a standing frame 2A is formed integrally on the other surface of the slide base 2. A laser diode light source element LD and photodiode reading and light-detecting elements PD1 and PD2 are positioned and fixed to the standing frame 2A, while a raising mirror M and a half mirror HM are arranged inside the standing frame 2A. An actuator 4 including an objective lens OL is further provided on the one surface of the slide base 2.
To describe the procedure of reading information, the disk D is rotated at a high speed and the actuator 4 is driven to move the objective lens OL in the focusing direction along a spindle 4a of the actuator 4 as well as to move the objective lens OL in the tracking direction, that is, in the radial direction X of the disk D around the spindle 4a. A laser beam “a” from the light source element LD is reflected at the half mirror HM and the raising mirror M to pass through the objective lens OL and be applied to the disk D, and then the reflected light “b” passes through the objective lens OL, reflected at the raising mirror M, and passes through the half mirror HM to be received at the reading element PD1. Thus, the information recorded on the disk D is read and the intensity of the laser beam “a” is detected by the light-detecting element PD2.
The configuration of a conventional optical pickup will be described with reference to FIGS. 8 to 13. FIG. 8 is a perspective view of the optical pickup; FIG. 9 is a vertical cross-sectional view around the light source element LD; FIG. 10 (a) is a view taken along the arrows D-D in FIG. 9 and FIG. 10 (b) is a view taken along the arrows E-E in FIG. 10 (a); FIG. 11 is a plan view around the reading element PD1; FIG. 12 is a front view of the reading element PD1; and FIG. 13 is a view taken along the arrows F-F in FIG. 11.
As shown in FIGS. 8 to 10, the light source element LD is fitted and fixed into a through hole 6a that is provided in the center of a rectangular metal block holder 6. An end portion of a flexible flat cable t1 connected by soldering 8a to terminal pins 7 of the light source element LD passes through an insertion opening 9 in the slide base 2 and enters between the slide base 2 and the main substrate 3 to be connected by soldering 8b to the main substrate 3.
To describe the procedure of positioning the light source element LD, the holder 6 is moved and positioned in the vertical direction Z and the horizontal direction Y with a protrusion 6b on the holder 6 being in contact with one side surface of the standing frame 2A, and the tilt of the holder 6 is fine-adjusted around the protrusion 6b. Then, the holder 6 is fixed to the side surface of the standing frame 2A by ultraviolet-setting adhesive or the like (not shown in the drawings).
As shown in FIGS. 11 to 13, the reading element PD1 is attached to a printed-wiring support substrate 11, and an end portion of a flexible flat cable t2 connected by soldering 8a to the support substrate 11 curves around the outer peripheral edge 2a of the slide base 2 and enters between the slide base 2 and the main substrate 3 to be connected by soldering 8b to the main substrate 3.
To describe the procedure of positioning the reading element PD1, the support substrate 11 is moved and positioned in the vertical direction Z and the horizontal direction Y with being in contact with one side surface of the standing frame 2A. Then, the support substrate 11 is fixed to the side surface of the standing frame 2A by ultraviolet-setting adhesive or the like (not shown in the drawings).
As shown in FIGS. 8 and 11, the light-detecting element PD2 is attached to a printed-wiring support substrate 12, and an end portion of a flexible flat cable t3 connected by soldering 8a to the support substrate 12 passes through an insertion opening 13 in the slide base 2 to be connected by soldering 8b to the main substrate 3.
To describe the procedure of positioning the light-detecting element PD2, the support substrate 12 is moved and positioned in the vertical direction Z and the horizontal direction Y with being in contact with one side surface of the standing frame 2A. Then, the support substrate 12 is fixed to the side surface of the standing frame 2A by ultraviolet-setting adhesive or the like (not shown in the drawings). It is noted that a related art is disclosed in Japanese Utility Model Laid-Open Publication No. Hei 5-27822.
As for the light source element LD shown in FIGS. 8 to 10, the clearance “α” between the insertion opening 9 and the main substrate 3 is significantly greater than the thickness “d” of the cable t1, as shown in FIG. 9. Therefore, if a tensile force “f” is applied to the cable t1 when the holder 6 is moved and positioned in the vertical direction Z, the tensile force “f” may concentrate at and thereby break the soldering 8b to result in a disconnection between the end portion of the cable t1 and the main substrate 3.
As for the reading element PD1 shown in FIGS. 11 to 13, the clearance “α” between the slide base 2 and the main substrate 3 is significantly greater than the thickness “d” of the cable t2, as shown in FIG. 13. Therefore, if a tensile force “f” is applied to the cable t2 when the support substrate 11 is moved and positioned in the vertical direction Z, the tensile force “f” may concentrate at and thereby break the soldering 8b to result in a disconnection between the end portion of the cable t2 and the main substrate 3.
As for the light-detecting element PD2 shown in FIGS. 8 and 11, the soldering 8b may also be broken in the same manner as described above to result in a disconnection between the end portion of the cable t3 and the main substrate 3.